The present invention relates generally to printed circuit board mounting apparatus and, more particularly, to apparatus which is adapted for being attached to a printed circuit board for protecting the solder fillets formed on the foil side thereof and, at the same time, facilitating the convenient screwless mounting of the board to a platform such as the bottom shelf of a television receiver or the like.
Printed circuit boards typically comprise a flat plate-like structure having a top surface on which is mounted a plurality of electronic components, the leads of the components extending through holes formed in the board and soldered to conductive paths formed on the foil or bottom surface of the board. The soldering process creates a plurality of solder fillets, sometimes referred to as "icicles," which depend from the foil or bottom surface of the printed circuit board and form both an electrical as well as a rather fragile mechanical connection between the component leads and the foil conductive paths. Thus, during the handling of assembled printed circuit boards it is not uncommon to find that one or more of the solder fillets have become damaged or broken as a result of, for example, placing the printed circuit board foil side down on a table or other flat surface. This may break the electrical connection established by the solder fillet thereby rendering the electronic circuitry mounted on the printed circuit board partly or wholly inoperative.
These problems are especially prevalent in industries such as the manufacture of television receivers where the printed circuit boards are typically assembled at a sub-assembly plant and then transported to a final assembly plant for mounting on the chassis of a television receiver. Thus, before being mounted in the receiver, the printed circuit board may be handled at a number of locations and by a number of people, each handling operation exposing the solder fillets to possible damage. Furthermore, after mounting the printed circuit board in the receiver, it is often necessary to remove the board for field service again exposing the solder fillets to possible damage.
The mounting of the assembled printed circuit boards on the television receiver chassis also presents certain problems. Conventionally, the boards are mounted on a flat shelf or platform in the receiver with a plurality of suitable screws being used to secure the printed circuit board to the mounting shelf. While not an extremely difficult assembly operation, this multiple screw fastening technique is relatively expensive from a labor and material viewpoint. In addition, the possibility always exists for one or more of the mounting screws to drop and be lost within the receiver resulting in a potentially harmful short circuit condition.
In view of the foregoing, it is a basic object of the present invention to provide novel apparatus which serves to protect a printed circuit board during handling thereof.
It is a more specific object of the invention to provide novel apparatus of the foregoing type which particularly serves to protect the mechanical integrity of the solder fillets formed on the foil surface of a printed circuit board during handling and transportation of the board.
It is an additional object of the invention to provide novel printed circuit board protection apparatus which further serves to facilitate the convenient screwless mounting of the circuit board on a mounting shelf or platform of a television receiver or the like.
In accordance with these and other useful objects, the present invention contemplates the provision of a novel snap action plastic rail, one such rail being attached to each of a pair of opposed edges of an assembled printed circuit board so as to space the foil surface of the board for protection from damage when placed on a flat surface. The rails include depending hooks or locking feet which, when slid and locked into retaining slots formed in a mounting platform, serve to securely fasten the printed circuit board to the mounting platform.